Electric heater



July 19, 1927.

A. JOHNSON ELECTRIC HEATER 4Filed July 29. 1925. 2 sheets-sheet 1 l IllIl .llllllllllz A 1,636,3 69 July 19 1927' A. JOHNSON ELECTRIC HEATERFiled July 29. 1925 2 Sheets-Sheet 2 1%, j 7 4. Hllilllmlllmnm v f P lj)10 mlm.

Patented July 19, 1927.

- UNITED STA Tes PATENT oFFlcs.

AXEL .ToNs'om OFOAKLAND, CALFORNIA.

ELECTRIC HEATER.v

Application sied July' a9, 15525'. pseriai No; 46,705.

in providing a special framework construc- `tion for the` heatingelements which removably mount the same therein in convenient andaccessible relation. y

Another object ot the invention resides in providing a heating elementof special construction having a substantially 'Hat rectann gular formprovided with end recesses receiving the terminal connections for theheating element Which is `Wound in a conti'n` nous groove formedthroughout the area of the element. j

The invention Y comprehends other im*- provementsresiding in theconstruction and arrangement of 'parts 'asinore particularly describedin the 'following detaileddescrip-- tion and in the claimV direc'tedmtoa' preferred construction of the invention7V it being understood,however, that various 'changes in the size, shape, and arrangement olthese parts may be made Without departing trom the spirit and scope otthe'rinvention as herein set forth; l

ln the drawings 'forming a part ot this application, f Y y l l ,m

Fig. l is a side elevation of awheating con duit showing the manner ofmounting the heating unit therein and also showing dia'- grammaticallythe circuit connectionsand switches 'lor controlling the energy supplyto the banks of heating units. y Fig. 2-is ran. enlarged plan view oivthe' rack showing the heating elements moun ed therein and the airconveying ,conduitv in section. y I Fig. 3 is a side elevation' ot'`therack and the heating elements,v portionsrof vvhich are broken awayand shown in section.

Fig. 4 is an endelevation ot the structure shown in Fig. 3.

Fig. 5 is a detailed longitudinal section on a substantially large scalethrough one end of one of th'e heating elements.

ll indicates an air conduit adapted tosupply air Jfor any suitablepurpose which is provided at 2 with an air intake and a'ta'n 3 forforcing air through the conduit. i door is provided at 4f giving accessto a portion ofthe conduit adjacent to the tan 3 so that the heatingunit indicated in dotted linesv bythe numeral 5A may be convenientlyinserted or removed from said conduit in the rear ot the tan 3' andwhich is adapted for uniformly heating the airbeing forced therethroughby the fan. lu the zoru'e'olltliel conduit receiving the `heating unitjthe same is lined throughout .theV inner surface With insulatingmaterial indicated at 6.

The heating'unit includes' a main frame made up cfa plurality ot'longitudinal angle bars 7 connected by the vertical and hori zontal endbars 8 and-9', respectively. A-

plurality ot' supporting bars l0 are mounted on the end bars 8 andextend longitudinallyy a'long each side of the trame. :These bars areprovided with notches in their upper edges, as indicated' at ll forreceiving. and holding the spreader bars" 12 in position: These spreaderbars are of inverted U-shape and extend transversely of the main frame"for support upon corresponding horiaontal supporting bars l0 at theyopposite sides ot' the as clearly shoivn in Fig. Ll.' These i spreaderbars mount a `plurality of pins 13, which project laterally from onesidethereof and receive and supportthe heating'elements 14 thereon. Thesespreader bars are L'rranged in pairs in Which the pins pro ject inopposed relation into the sockets 15 formed inthe upper edgesot the endsof the heating elements lll as clearly shovvnin 3;v In this Wayitjwillbe noted that the spreader bars are removably mounted inthe notchesinthe supporting bars l() and re'- movably but yet rigidly mount theheating elements le in j'nedetermined spaced rela*- tion Within thecontines of the main frame.

vAs shown particularlyin Fig. 2 the heating elements in ditlerent banksor between dilitere'nt pairs of spreaderbars are mounted so as to be instaggered relation relative to the direction ot' tlow through theltraine.

Each ofthe heating elementsare of similarV construction and comprise asubstantiallyV liat molded body of suitable insulating material. Theseelements are of substantially rectangular kformation and have the upperly extending grooves 19 1n and lower edges rounded as illustrated in thedrawings. The end portions are provided with cut out sections orrecesses 16 which provide end lugsfl? for receiving the terminals 18 forthe heatin element. Y These molded bodies are provide with transversethefaces thereof which are interconnected around the curved edges so that`a continuous substantially s iral groove is formed from end to end of te elements in which the grooves in one side and at one end are. arrangedin a substantially vertical or transverse relation in the body of theelement while the grooves pro-v gressing towards the opposite end on thesame side of the body are formed therein at successively increasingangles. The grooves on the opposite side of the body are formed in thesame manner with substantially vertical or transversely extendinggrooves while at the opposite end the saidV grooves inclinesuccessively, these grooves being arranged in the reverse relation tothe grooves in the other side. The heating element 20 is formed of asubstantially helical resistance wire laid in said grooves 19 andsecured therein by suitable fireproof material which firmly cements theheating coil in the grooves for the purpose of preventing sagging andthe like. The particular formation of they grooves permits the use ofthe entire area of the body of the element for receiving portions of theheating element therein in order that a heating coil having amaximumlength may be wound over substantially the entire area in orderthat the element may at the same time be made of small size. Theparticular relation of the grooves as above described aids in providinga heating element structure of minimum slze. and at the same timecarrying the maximum length of heating coil. The heads of the bindmo`posts 18 are slotted and receive the ends ofp the heat-k ing element 2Ofrom the end portion ofthe groove in the body ofthe element which headportionv is swagedover the endv of the wire 20 of the heating coil foreffectively retaining the heating coil in direct electrical cfmnectionwith the binding post without other securing means. Lock nuts 21 securethe binding posts 18 in the body of the'element while the bus bars 22having a plurality of openings in spaced relation lit over the ends ofthe binding'posts 18 andare rigidly connected thereto by the use ofadditional lock nuts so that the several heating coils on the heatingelements are connected in the circuits made with the bus bars inparallel. The ends of the bus bars 22 are formed with sockets 23 whichreceive the ends of the cables 24 used for connectin the several banksofheatin elementswit the icontrolmotely to the main framework and theheating unit. A main control switch 26 may also be provided forcontrollin the connection of thel-heat'ing'elements w1th sources ofpower of Vdifferent voltage or from different sources. As shownparticularly in Fig. 2 the cables 24 extend through insulating sleeves27 mounted in the side of the conduit 1 and :extending throughinsulating section 6.

As shown in the drawing a plurality of heating elements 14 are mountedbetween each pair of spreader bars to form a bank of heating elementswhich are removably supported on the bars 10 and opposite sidesl ofthemain frame. As shown there arc a plurality of banks arrangedhorizontally in which the heating elements of each adjacent bank aremounted in staggered relation to produce even heating of airlowingthrough the frame. It will also be noted that there are aplurality of vertically arranged banks of heating elements su orted bydifferent pairs of bars 7 in spaced)liorizontal planes.

n this way a substantially open and readily disassembled structure isprovided for a plurality of banks of heating units in which the unitsthemselves are removably mounted between pairs of spreader bars whilethe spreader bars are removably seated in the notches of the supportingbars 10. A further feature of the invention resides in the constructionof the heating element which is provided with recesses for removablyreceiving the pins of the spreader hars and provided with cut outortions in the ends mounting the terminals or the heating coil while atthe same time utilizing the entire surface of the body for receiving aheating element in a predetermined manner.

What is claimed is: i

A heating unit comprisin an open frame work having a plurallty oparallel spaced horizontal bar members dis sed in superimposed pairs atopposite side0 pairs of parallel supporting barsfremovably resting inpredetermined spaced relation at opposite ends on opposing bar membersof the respective pairs, a plurality of elongated heating elementsdisposed in parallel spaced relation vbetween sa1d pairs of supportingbars and secured at their ends thereto forming with said supporting barshorizontal and vertical rows of batteries of heating units, eachhorizontal row being independently rcmovable from said frame, theheating element between each adjacent pair of su porting bars beingpositioned in staggere rela-` tion with one another. y

In testimony whereof I have signed` my yname to this specification.

AXEL. JOHNS@ s of the frame,

